A Preventive Intervention Research Center is proposed, based in the Department of Mental Hygiene of The Johns Hopkins University School of Hygiene and Public Health but including other departments and divisions of the University. The goals of the Center are: - to design, implement, and evaluate preventive trials directed at increasing the effectiveness of the child's behavioral responses to school; - to develop methods and instruments for research in preventive interventions; - to develop a preceptee program for new investigators in prevention research; - to disseminate information to the scientific and lay communities about prevention in mental health. A conceptual model is proposed -- community epidemiology with a life-span-developmental orientation -- that focuses attention on social task demands and behavioral response in children and that integrates the broad set of disciplines necessary for effective prevention research in this area. The model, together with a growing body of longitudinal epidemiological studies, suggests that early childhood risk behaviors identified in school are promising targets for prevention trials. Specific projects are proposed that will use data from a periodic child epidemiological assessment system in the eastern half of Baltimore already the site of the recent NIMH adult epidemiologic project. - the Mastery Learning Trial: To assess the effect of improving learning in first and second grade on psychiatric symptoms, delinquency, disorders, and other outcomes; - the Good Behavior Game Trial: To assess the effect on delinquency, symptoms, disorders, and other outcomes of improved classroom management of aggressive and shy behavioor in first and second grade; - the Behavioral and Diagnostic Epidemiological Assessment Project: To measure the incidence and prevalence of risk behaviors, symptoms, and mental disorders in elementary school children in Eastern Baltimore, and to assess the relationship of classroom behavioral measures to symptom measures, and to clinical diagnoses; - the ECA-Family Project: To assess the relationship between household structure and adult mental disorder measured in the earlier NIMH epidemiological study, to children's classroom behavior, symptoms, and clinical diagnoses. Fifteen schools in Eastern Baltimore will be targeted for intervention in the two trials and related research. Close collaboration exists with the public schools.